1. Field of the Invention
The invention relates to a vibration damper with variable damping force.
2. Description of the Prior Art
German reference DE 44 03 196 A1 describes, in FIGS. 3a to 3c, a vibration damper with variable damping force in which the extent of the change in the damping force depends on the deflection distance. This involves a load-dependent damping force modification that only functions in connection with a spring-and-damper unit, because a vehicle suspension spring or stop buffer must act as the actuator. In compact cars, as a rule, the vibration damper is a spring-and-damper unit. However, mid-sized and large vehicles are often also equipped with vibration dampers in the form of axle dampers. In this case, the vehicle suspension spring that acts as the actuator for load-dependent damping force modification is omitted.
Alternatively, of course, an adjustable damping valve with electric activation can be used, as FIG. 5 of the aforementioned reference discloses. However, vibration dampers of this type entail considerable expense, especially with respect to ensuring reliability in the event of system failure.